I could have said it without refering to tuna fish........sorry, my bad.

 

Reliable reference? Half of one perhaps, it's the bottom of a range with the top obviously being the actual coolant temperature. It is also well known that good oil pressure on a 4.0 is about 30-40 PSI at hot idle. My point is that, according to the FSM, it's not worth fixing unless it's below 13. That in no way implies that 14 PSI is healthy. If you had a brand new I6 and it only built that much pressure I would be really concerned.

Unfortunately this is the problem when no real numbers are available for reference. It leaves what "should" be "normal" up to speculation at the worst and research into a real-world average. You can't rely on the FSM for anything other than what Chrysler thought was worth their time to fix or what customers would tolerate, and trying to call it anything else is just as misguided as speculation. By it's very definition, it is a guide on how and when to fix things, not an engineer's specifications book (for example it doesn't list the diameter of the rotors for front brakes).

Agreed.

 

Whatever......

 

Exactly. There is no *normal* temp given in the FSM. The bare minimum doesn't really prove ****, other than the heater core isn't clogged and the blower motor functions well enough. As I've said before and others the OP needs to verify the oil pressure with mechanical gauge. If he actually has 80psi cold he must have some restrictions causing the increased pressure, I highly doubt this and lean more towards wiring or a faulty gauge since he's replaced the pressure sensor.

This thread has gone on 4 pages longer than it should have. There are 2 steps the OP needs to take.

1) Factory thermostat
2) Verify oil pressure readings with a mechanical gauge

Report back once that has been done.

 

I love tuna fish. Holy mackerel!

 

Excellent advice. OP, get your butt in gear right away.

 

Wouldn't the bare minimum (144F @ 60F ambient) indicate to a technician, in addition to the heater core not being clogged and blower motor functions correctly, that the doors in the HVAC box operate/seal correctly, the vent selector is functioning correctly, the temp selector is functioning correctly and coolant temp has reached 195F+? I guess those 6 items functioning correctly wouldn't prove ****, would they?

 

Well, I did read through. I'm wondering what kind of driving. If it never warms up at idle and short easy trips, but DOES warm up when say climbing a hill for a few minutes, might it possibly be just too rich?

That's what mine seemed to do. Just doesn't seem to make sense though, I would hope the T-stat would bring it to 190...ish. Maybe my non-OEM was opening before 190.....

 

Factory stat is the only way to go. I learned the hard way.
You wouldn't get the fuel economy that you do if it was running that rich.

How old is your O2 sensor?

 

checked with jeep dealers in a hundred mile radius. none in stock. had to order. supposed to be here tomorrow (Friday).

last weekend drove it nonstop at 70 mph (over 2000 rpm's) for 130 miles and the gauge stayed at 1/8 position.
pulled a 16 ft boat last summer (about 20 miles at 55 with some hills) and it got almost to the straight up position, 210 degrees.

 

1/8 mark is 127.5.........impossible that's correct......even if u were running without a t-stat. It's possible, that last summer pulling a boat up hills, the 210 reading could have been wrong (low) as well.

 

the verdict is in!

i put the mopar tstat in today. the old one (pictured below) WAS stuck open. it looked like it had opened too far and caught itself on a safety mechanism. holding the old stat next to the new one was interesting. the mopar stat looks much better built. the parts store one looked like it was made for a tonka truck.

after installing the new stat i started the engine. it didn't warm up very fast but i think a little faster than before. it achieved full operating temp while idling (just under 210 mark). drove down the road and it started to fall.....but then you could see the stat was closing to maintain proper temp. bounced between 180 and 210 during the ten minute test drive. the oil pressure stayed at 70+ at idle even at full temp. after the test drive it had dropped to 40 idling and 60 driving. right where it should be. tested the heat (through the vents again) and the pen thermometer read 170 (dash gauge temp bout 190). it was 15-20 degrees cooler today than when i tested it before.

lesson learned. nothing but mopar parts for my xj from now on! especially thermostats. still idles at 1200 rpm in park at 200 degrees though.....think i'll start a new thread for that problem. it would probably be a good idea to lock this one.

 

Those are "fail safe" thermostats, they are designed to catch on a latch if the wax heats up enough due to overheating. Usually they suck, as you now know.

 

Have you verified your oil pressure with a mechanical gauge yet? If not forget about what your oil pressure gauge says and verify it ASAP.

 

Oh no, "fail safe" strikes again. Still seems odd that a new (Mopar at that) 195F stat would yield a 180 cooolant temp reading. Me still thinks the gauge(s) are wacked. After having the oil pressure tested/verfied, install a Mopar oil pressure sending unit.